CN107206674B - Three-dimensional printing system, computer-implemented method, and computer-readable storage medium - Google Patents

Abstract

The present invention relates to a three-dimensional printing system, a computer-implemented method, and a non-transitory computer-readable storage medium encoded with a computer program, the system comprising: (i) a resin container; (ii) a plurality of rods (103); (iii) a plurality of light sources (104) arranged to emit radiation into the plurality of rods (103) such that radiation passing through a given one of the rods (103) cures the liquid resin (105) surrounding the given rod (103) when the cavity contains liquid resin (105); and (iv) a control system (110) configured to: (a) receiving data specifying a three-dimensional structure; (b) determining a shape of a layer of a plurality of layers that collectively form a three-dimensional structure; and (c) determining one or more of the light sources (104) corresponding to the shape of the layer; and (d) forming the layer by operating one or more determined light sources, the one or more determined light sources corresponding to a shape of the layer.

Description

Three-dimensional printing system, computer-implemented method, and computer-readable storage medium

technical field

The present invention relates to a three-dimensional printing system, a computer-implemented method, and a non-transitory computer-readable storage medium encoded with a computer program.

Background technique

Three-dimensional ("3D") printing is an additive manufacturing process in which successive layers of material are laid on top of each other to form a solid 3D object. Over time, various types of 3D printing processes have been developed, including extrusion-based 3D printing (eg, Fused Deposition Modeling (FDM)) and photopolymerization-based processes such as Stereolithography (SLA) and Digital Light Processing (DLP) and more.

In a stereolithography process, a 3D structure is built one layer at a time, with each layer formed by exposing a photoreactive resin to an ultraviolet (UV) light source that cures the resin. Note that stereolithography may also be referred to as optical fabrication, photocuring, and/or solid-state free-form fabrication and solid-state imaging.

More specifically, in a typical stereolithography process, a user creates a digital 3D model of an object through a software interface of a 3D printing application. The 3D printing application then cuts the 3D model with a set of horizontal planes. Each slice of the 3D model can then be converted into a two-dimensional mask image such that the 3D model is represented as a sequence of two-dimensional mask images, each two-dimensional mask image outlining the shape of the corresponding layer of the 3D model. The mask image is sequentially projected onto the photocurable liquid or powder resin surface while light is projected onto the resin to cure it in the shape of the layer. Alternatively, instead of using a mask, each slice of the 3D model can be represented by a two-dimensional image of the shape of the slice, so that a projector can project a sequence of such two-dimensional images onto the resin surface to form an object corresponding to the digital 3D model .

SUMMARY OF THE INVENTION

Example embodiments relate to three-dimensional printing systems and methods. 3D printing using stereolithography can be a time-consuming process. More specifically, in a typical stereolithography process, it takes a considerable amount of time to guide a spotlight along a path to cure each layer of a 3D object. Exemplary embodiments may allow faster curing of each layer of the 3D object by providing rods through which light passes to cure the resin around the light-emitting rods.

For example, in an exemplary embodiment, a 3D printer may use stereolithography to form each layer by selectively curing specific voxels that form the shape of the layer. To do so, the 3D printer may include a plurality of light sources, each arranged to project light through a corresponding rod extending into the vat of curable liquid resin. The rods can be arranged in a grid such that light emitted from each rod can solidify a predetermined shape of voxels surrounding the rod. Furthermore, the grid of rods may be arranged such that adjacent rods will solidify voxels that are adjacent to each other, such that the solidified voxels are connected and together form a layer. For example, each rod can be configured to solidify hexagonal voxels so that "honeycomb" layers of various shapes can be formed.

In one aspect, the system includes: (i) a resin container defining a cavity, wherein the cavity is partially defined by an inner base surface of the resin container; (ii) a plurality of rods extending from the inner base surface to in said cavity; (iii) a plurality of light sources arranged to emit radiation into said plurality of rods such that when said cavity contains liquid resin, radiation through a given one of the rods cures a liquid resin surrounding a given rod; and (iv) a control system configured to: (a) receive data specifying a three-dimensional structure; (b) respectively determine a first layer and a first layer from a plurality of layers that together form the three-dimensional structure a first shape and a second shape of two layers; (c) determining one or more of said light sources corresponding to said first shape; (d) forming said first layer by operating one or more light sources, the one or more determined light sources corresponding to the first shape to cure the liquid resin in the first shape; (e) determining one or more of the light sources corresponding to the second shape; and (f) solidifying the liquid in the second shape by operating one or more light sources to form the second layer on the surface of the first layer, the one or more light sources corresponding to the second shape resin;

In another aspect, a system includes: (i) a resin container defining a cavity, wherein the cavity is partially defined by an inner base surface of the resin container; (ii) a plurality of rods extending from the surface of the substrate into said cavity; (iii) a plurality of light sources arranged to emit radiation into said plurality of rods such that when said cavity contains liquid resin, radiation passing through a given one of the rods curing a liquid resin surrounding a given rod; (iv) a substrate suspended from above the resin container and configured to adhere to the cured resin; and (v) a control system configured to: (a) receive a specified three-dimensional structure data; (b) determining a first shape and a second shape of a first layer and a second layer, respectively, from a plurality of layers that together form the three-dimensional structure; (c) determining in the light source corresponding to the first shape (d) forming the first layer by operating one or more determined light sources, the one or more determined light sources corresponding to the first shape, to cure in the first shape a liquid resin; (e) determining one or more of the light sources corresponding to the second shape; and (f) forming the second light source on the surface of the first layer by operating the one or more light sources layer, the one or more light sources corresponding to the second shape to cure the liquid resin in the second shape.

These and other aspects, advantages and alternatives will become apparent to those of ordinary skill in the art upon reading the following detailed description with reference to the appropriate drawings. Furthermore, it is to be understood that the description provided in this general section and elsewhere in this document is intended to illustrate the claimed subject matter by way of example and not limitation.

Description of drawings

1A shows a side view of a three-dimensional printer system according to an example embodiment.

FIG. 1B shows a top view of a three-dimensional printer system according to an example embodiment.

2A-2F illustrate example operation of a three-dimensional printer system according to example embodiments.

3A-3D illustrate example operation of a three-dimensional printer system according to another example embodiment.

FIG. 4 shows an example program logic module for interfacing with and controlling the three-dimensional printer system.

FIG. 5 is a flowchart illustrating a three-dimensional printing method according to an example embodiment.

FIG. 6 is a flowchart illustrating a three-dimensional printing method according to another example embodiment.

Detailed ways

The following detailed description describes various features and functions of the present disclosure with reference to the accompanying drawings. In the figures, similar symbols typically identify similar parts, unless context dictates otherwise. The illustrative devices described herein are not meant to be limiting. It will be readily appreciated that certain aspects of the present disclosure may be arranged and combined in various different configurations, all of which are contemplated herein.

I. Overview

Example embodiments relate to three-dimensional printing systems and methods. In particular, an example 3D printer may include a robotic arm or another robotic device that suspends a substrate above a container filled with a photoreactive resin. The container may include a rod extending upwardly from the base of the container. In some embodiments, the rods are arranged adjacent to each other to form a grid or lattice. A light source operated by the control system can distribute electromagnetic radiation through the rod, which causes the resin surrounding the rod to cure.

The control system may receive data representing the 3D structure. The control system may divide the three-dimensional structure into layers that, when stacked, form the 3D structure. Each layer can then be divided and/or approximated into voxels. A "voxel" can be understood as a three-dimensional space with a predetermined shape and volume. In this way, each layer may be formed from voxels that are in the same plane and that together form the desired shape of the layer.

More specifically, to form the initial layer (eg, the first layer) of the 3D object, the substrate of the 3D printer can be lowered into the resin such that the substrate contacts the top of the rod. The control system can then operate the one or more ultraviolet (UV) light sources to emit radiation into their corresponding rods. UV radiation from each source passes through each corresponding rod and into the surrounding resin, which cures the surrounding resin to form voxels around the rod. The voxels solidified around multiple rods together make up the first layer of the 3D object. In particular, the layer may include adjacent voxels, which may be formed as a single voxel and/or as a continuous segment of cured resin. When cured, the voxels can adhere to the substrate, and the substrate can be moved upward so that the next layer of voxels can be formed on the lower surface of the first layer.

In particular, the adhesive layer of the substrate and cured resin can be moved upwards until the bottom of the cured layer is positioned on top of the rod. The control system can then operate the 3D printer to cure the one or more voxels to form a subsequent layer (eg, a second layer) of the 3D structure that adheres to the previous layer above it. The process of lifting the cured layer from the rod and curing subsequent layers can then be repeated for each layer to form a 3D structure under the previously cured layer.

Another exemplary 3D printer may be configured with a resin-filled container and substrate. However, in this exemplary embodiment, the rods may extend from the base plate down into the resin. Initially, the substrate can be dipped into the resin so that the rods are in contact with the bottom of the container. The control system can cure the voxels in a similar manner as described above to form a layer of the 3D object, which after curing can be detached from the stem and rest on the bottom of the container within the resin. The substrate can then be lifted up until the lower ends of the rods are positioned on top of the initially cured resin layer. The process can then be repeated, forming subsequent layers adhered to the layer below it to form the 3D object within the resin.

By providing two or more light-emitting rods within the resin, the example 3D printers described above may allow for faster formation of 3D objects; for example, compared to solid layer methods. Forming a layer from a voxel as described above may require significantly less time than conventional methods of curing a resin layer using a concentrated light source. For example, since the cured voxels are partially hollow, a smaller volume of resin may be required to form each layer, allowing for shorter curing times. Furthermore, depending on the size of the rod, each layer formed can be thick (ie, tall), allowing for the rapid formation of large 3D objects. Furthermore, since multiple voxels are formed simultaneously, each layer can be formed in a fraction of the time compared to the time required to direct a concentrated light source along the shape of the layer.

It should be understood that the possible benefits described above and elsewhere herein are not required. Furthermore, other benefits are possible.

II. Exemplary 3D Printing Systems

1A shows a 3D printer system 100 according to an example embodiment. The 3D printer system 100 includes a resin container 102 and a light source, such as light source 104, coupled to a rod, such as rod 103, extending from the base of the resin container. The light source is operable to emit electromagnetic radiation that passes through the rod and into the resin 105 . The radiation can cure a portion of the resin 105 that surrounds the rod through which the radiation passes. Additionally, the 3D printer system 100 includes a robotic arm 106 having a substrate 108 attached thereto.

The robotic arm 106 is operable to position the substrate 108 over the resin container 102 and to move the substrate 108 relative to the resin container 102 in at least one degree of freedom (up and down). In some embodiments, the robotic arm may be operable with at least three degrees of freedom to allow the substrate 108 to be parallel to the base of the resin container 102 in addition to upward movement away from the resin container 102 and downward movement towards the resin container 102 Lateral movement. In some embodiments, the control system may be capable of setting the orientation of the substrate and/or the translation of the substrate. Other embodiments may also allow additional degrees of freedom.

Note that 3D printer systems can mount substrates to various types of robotic devices and are not limited to robotic arms. For example, the base plate can be mounted on a dual-axis head unit or an articulated robotic arm with four degrees of freedom. Other example robotic devices are also possible.

The substrate 108 may be implemented as an end effector on the robotic arm 106 . Other gripping and/or gripping robotic mechanisms may also be implemented to hold and lift one or more layers of cured resin from resin 105 . Additionally, the robotic arm 106 may be programmable such that a set of control commands can be generated to move the robotic arm 106 in a manner that results in the creation of a particular object on the substrate 108 .

Depending on the particular embodiment, the substrate 108 may vary in size and/or shape. Furthermore, depending on the particular embodiment, the substrate 108 may be formed from various materials or combinations of materials. In general, the surface of the substrate 108 may be formed of any material to which a base layer of resin will adhere when cured. Additionally, since the substrate holds the printed object from above, the size, weight distribution, shape, and/or adhesion of the substrate surface facing the resin container can be designed to provide support for a specific load (eg, so that the substrate can hold up to objects of a specific weight, shape and/or size).

Resin container 102 may have various sizes and/or shapes depending on the particular embodiment. In some cases, resin container 102 may be large enough to allow the 3D printing system to form the entire 3D object within resin 105 .

The light source may be any controllable light source that emits electromagnetic waves from a suitable region of the electromagnetic spectrum for curing resin 105 . In some embodiments, the light source may be controllable to emit ultraviolet (UV) light. The brightness of each light source can also be varied individually in a continuous analog fashion or using digital techniques such as pulse width modulation. When forming a given layer, the intensity of light passing through each rod can be individually controlled. Note that "brightness" may refer to the luminous intensity of light. The light source may be embedded within the rod, positioned above or below the rod (depending on the particular embodiment), or may be provided from a remote location and guided into the rod using optical fibers or other waveguides. Some exemplary light sources include incandescent light bulbs, light emitting diodes (LEDs), gas discharge lamps, or lasers covered in UV filters. Other light sources can also be used.

Note that a light source emitting radiation is represented in the figure as a thick arrow pointing outward from the light source. For example, in Figure 2A, each of the light sources depicted is emitting light. In Figure 2B, none of the light sources depicted are emitting radiation. In Figure 2B, none of the light sources depicted emit radiation. As a further example, some of the light sources depicted in Figure 2C are emitting radiation. When the emitted light is represented as an arrow, the light or other electromagnetic radiation emitted from the light source may not necessarily be directional. In some cases, the radiation is scattered (ie, the light source "glows") such that it is not directed to any particular location or direction. Radiation scattering can be achieved by using a wide angle light source or by coating, grinding and/or etching the light source itself. Additionally or alternatively, the rods may be etched, frosted, coated, or otherwise configured to scatter radiation from the light source. Any combination of finishing processes and/or other scattering techniques may be performed to scatter radiation emitted by the light source and through the rod into the resin surrounding the rod.

A mechanism or device may be coupled to the base of the resin container 102 or to the rod itself to help separate the cured resin from the rod. For example, a vibrating mechanism such as a vibrating motor can be attached to the resin container or rod to shake the cured resin loose from the rod. As another example, a cooling element, such as a heat pump, may be coupled to a rod that, in response to being cooled, causes the rod to thermally shrink and separate from the cured resin. Other temperature changing elements may also be coupled to the rod to heat and/or cool the rod. As another example, a gas outlet may be positioned around the stem around the base of the container 102, which assists in separating cured resin from the stem by venting gas into the resin. In some embodiments, the base of the resin container 102 may allow the rod to be rotated in place or retracted into the base of the resin container 102 . Additionally, the rod may be at least partially coated in a non-stick coating, such as polytetrafluoroethylene (PTFE) or other low friction coatings or lubricants.

The rod may be made of one or more materials that allow light emitted from the light source to pass through. The rods can be configured to scatter light to evenly distribute light passing through them. In some embodiments, the rod can be made of a transparent or translucent material, such as glass or translucent plastic. The rods can be frosted, etched, coated in a substance, or any combination thereof to scatter the light passing through them. The rod can be solid or partially hollow. The rods can also be of any size and/or depend on the particular embodiment.

Rods can take various shapes. FIG. 1B depicts a top view 120 of the 3D printer system 100 according to certain embodiments. In this embodiment, rods such as rod 103 are shaped as hexagonal columns. The rods shown in Figure IB are arranged as a two-dimensional lattice (more specifically, tiling as chamfered hexagons). During operation, radiation passing through a given rod solidifies the resin in the channels around the rod to form voxels. Thus, the thickness of the voxel corresponds to the space within the channel surrounding the rod.

Any number of rods may exist within a particular 3D printer system. Rods can be shaped as cylindrical tubes, triangular columns, rectangular prisms or octagonal columns. Other rod shapes are also possible. The arrangement of the rods may vary depending on the specific rod shape and/or embodiment. For example, the rods can be arranged in a two-dimensional grid. Other arrangements are also possible. Furthermore, one or more rods may be omitted from the lattice or grid, depending on the specific implementation. Other examples are possible.

The build volume of an example system such as 3D printer system 100 may be defined, at least in part, by the range of movement and/or the reachable distance of the robotic device on which the substrate is mounted. For example, in FIG. 1 , the build volume may be defined by the range of movement of the robotic arm 106 . Other examples are possible.

Additionally, exemplary embodiments such as 3D printer system 100 may allow for the creation of objects that are much larger than can be created in a 3D printer, where the build volume is determined by the size of the disk (eg, the surface area of the resin container 102 ) and/or the substrate limited surface area.

In some exemplary embodiments, robotic arm 106 is operable to move laterally to offset the position of one or more voxels in a particular layer. Figures 2E and 2F, discussed in more detail below, depict example lateral offsets between layers.

In another embodiment, the rods may extend downwardly from the base plate 108 . The 3D printing system according to this embodiment can form voxels in a similar manner as described above by curing resin around the rod by passing light emitted from a light source through the rod. The voxels can then be separated using at least one of the techniques described above. In some cases, the initial layer may be adhered to the base of the container or a separate platform placed on the bottom of the container.

In other embodiments, the rod may be positioned at an angle within the resin container. Alternatively, the rod may be positioned along one side of the resin container 102 . Other rod placements are also possible.

III. Operation of the Example 3D Printer System

2A-2F illustrate example operation of a 3D printer system according to example embodiments. More specifically, FIGS. 2A-2D illustrate an order in which two layers of a 3D object are formed according to an example method, such as method 500 . 2E and 2F illustrate example operations involving lateral offsets between shaped layers.

FIG. 2A depicts the 3D printer 200 during a curing operation of an initial layer. The base plate 108 is positioned so that it is in contact with the rod. In a curing operation, each light source may selectively emit radiation that cures the resin around each rod to form voxels. For example, voxels 202 may be solidified around rod 103 . Additional voxels (not labeled) can be selectively cured around each of the other rods shown in Figure 2A. Voxel 202 and other voxels solidified parallel to voxel 202 may collectively form an initial layer adhered to substrate 108 .

Figure 2B depicts the 3D printer 200 during a lift operation with the voxels of the initial layer separated from the rod. Before starting the lift operation, turn off the light source to prevent excessive curing during the lift operation. As shown in Figure 2B, the voxels of the initial layer adhere to the substrate 108 being lifted upwards, separating the formed voxels from the rods around which they were formed. The 3D printer 200 can manipulate the substrate 108 so that the bottom of the initial layer is positioned at the top of the rod. In some cases, the distance is predetermined based on a known fixed height of the rod.

Figure 2C depicts the 3D printer 200 during a curing operation of subsequent layers. After the lift operation is complete, some light sources are turned on and emit radiation to cure the resin, forming subsequent layers. Voxels of subsequent layers, such as voxels 204, may be adhered to voxels of the previously formed initial layer during the curing operation. Note that the substrate 108 is no longer submerged within the resin 105 during the curing operation shown in FIG. 2C.

Figure 2D depicts the 3D printer 200 during a lift operation with subsequent layers of voxels detached from the rod. The lifting operation shown in FIG. 2D is performed similarly to the lifting operation shown in FIG. 2B .

The operations shown in Figures 2A to 2D may be repeated any number of times to form any number of voxel layers.

Figure 2E depicts the 3D printer 200 including a lateral offset during the curing operation of the subsequent layers. The curing operation shown in Figure 2E is similar to the curing operation shown in Figure 2C, except that prior to operating the light source, the substrate 108 is moved laterally to create an offset between the initial layer and the rods. After the lateral alignment of the substrate 108 is completed, the light source is operated to cure the voxels forming the subsequent layers. As a result of the lateral offset, each voxel in a subsequent layer may adhere to portions of multiple voxels of the initial layer. In this way, finer-grained differences between layers (ie, "sub-voxel" divisions) can be formed.

Figure 2F shows a lift operation 250 that separates laterally offset voxels of subsequent layers from the rod. The lift operations may be similar to lift operations 210 and 230 .

The operations of Figures 2E and 2F can be repeated, using a different amount of lateral offset for each offset. Note that although the offsets depicted in Figures 2E and 2F are shown in one dimension, the lateral offsets may be two-dimensional offsets.

The lateral shift operations shown in Figures 2E and 2F may be performed multiple times for a particular layer (which may be referred to herein as "multi-phase shifting" or "multi-phase alignment") to form multiple shifts within a particular layer . In some cases, the shape of the layer can be more precisely formed if the voxel offsets are incorporated within the layer. The layer-to-layer offsets described here may allow 3D printing systems to simulate printing at higher resolutions than otherwise permitted by grids or lattices of rods.

As an exemplary operation, a subset of the light sources may be initially manipulated to cure one or more voxels representing a portion of the shape of the layer. The rod corresponding to the initially operating light source can then be retracted into the base of the resin container, detaching the cured voxels from the rod, and allowing the substrate to move without destroying the cured voxels adhered to it or damaging the rod . Then, the substrate is laterally shifted by a predetermined amount. After positioning the substrate, another subset of the light sources may be manipulated to cure one or more voxels representing another portion of the shape of the layer. Collectively, these two parts can make up the layer. The substrate can then be lifted, the cured voxels removed from the rod and the formation of the layer completed. Alternatively, subsequent portions of the same layer may be performed by retracting rods and moving the substrate as described above.

Other bar arrangements are possible allowing for interlayer offsets. For example, the rod may be controllable to move within a predefined range. As one example, each rod can be manipulated individually to move along the track, so that a specific spacing between each rod can be specified for a given layer. Other bar arrangements that allow for inter-layer offsets are also possible.

Note that the voxels depicted in Figures 2A to 2F and the voxels shown in Figures 3A to 3D are shown to have specific shapes and thicknesses. In other example operations, the shape and thickness of the voxels may vary. Additionally, the voxels are shown to include at least 3 sides formed from resin surrounding the sides and top of the rod. For explanatory reasons, voxels are displayed in this manner. In some embodiments, radiation can pass through the sides of the rod, but is prevented from passing through the top of the rod. In such embodiments, voxels are formed around the rod, but not above or below the rod, such that the formed voxels are columns with hollow centers.

3A-3D illustrate example operation of a 3D printer system according to another example embodiment. The operations depicted in Figures 3A-3D are similar to the operations depicted in Figures 2A-2D, respectively. However, the rods of the 3D printer system shown in Figures 3A to 3D extend down from the substrate into the resin. The 3D printer system shown in Figures 3A to 3D may also include various mechanisms and devices as described above. Various techniques that can be used to separate the cured voxels from the rods can also be incorporated on the substrate 108 . Additional repetitive descriptions are omitted; however, it should be understood that the above-described operations may be applied to this exemplary embodiment.

It should be understood that Figures 2A-2F and Figures 3A-3D are provided for illustrative purposes and are not intended to be limiting. Other 3D printing systems that form voxels are also possible. Furthermore, it should be understood that any combination of components may be arranged in various ways for a particular 3D printing system and that they may operate the same or similar to those described with respect to FIGS. 2A-2F and 3A-3D without departing from this invention range.

IV. Control of Example 3D Printer System

Referring again to FIG. 1A , the 3D printer system 100 may also include or be communicatively coupled to a control system 110 . Control system 110 may take on or include executable program logic, which may be provided as part of or in conjunction with 3D printer system 100 . Such program logic may be executed, for example, to generate control signals for the 3D printer system 100 . For example, a number of program logic modules may be included as part of a control system such as control system 110 .

In an example embodiment, the control system 110 is operable to (a) receive data specifying the 3D structure, (b) determine the shape of each of the two or more layers that together form the 3D structure, and (c) ) forming each of the two or more layers by (i) determining one or more light sources corresponding to the determined shape of the layer, and (ii) manipulating one or more of the determined layers The light source cures the layer of liquid resin having the determined shape. The control system 110 may also operate the robotic arm 106 after curing the liquid resin layer to move the substrate upward so that the bottom surface of the cured layer is positioned at the top end of the rod. The control system can repeat these operations to cure multiple layers of resin, forming a 3D structure in a layer-by-layer fashion.

Figure 4 shows an example program logic module for interfacing with and controlling a 3D printer system. In particular, the 3D modeling application 450 and corresponding graphical user interface (GUI) 452 may allow for 3D model generation. Additionally, in order to prepare the 3D model for printing, the model processing module 454 may apply slicing processing to the 3D model. For example, various techniques may be used to define a set of voxels of the 3D model representing a solid portion of the 3D model. Each voxel can be associated with a three-dimensional position. Layers of a 3D model may be defined by voxels that lie within a particular plane (eg, voxels with different width or depth positions but at the same height).

In some cases, the 3D model can be represented as continuous lines and/or curves (eg, vector graphics). Model processing module 454 may rasterize the vector-based 3D model to generate sets of discrete voxels that represent the 3D model at a particular resolution. Resolution can depend on the number of bars in a given 3D printer system.

In other cases, a 3D model may be represented as a group of discrete voxels at a particular resolution that is not compatible with a given 3D printer system. Model processing module 454 may use digital techniques to upscale or downscale the 3D model so that the resolution of each layer matches the capabilities of a given 3D printer system. Other examples are also possible.

The segmented 3D model can then be passed to both: (i) robot control module 456, which can generate robot control signals; and (ii) image coordination module 458, which can generate image control signals that are used as signals for 3D printing , including image files and light source control signals to print 3D objects based on 3D models. Additionally, note that the robotic control module 456, the image coordination module 458, and/or other program logic modules may utilize the timing of the image control signals to coordinate the timing of the robotic control signals so that the 3D printing process executes appropriately.

V. Illustrative Methods

FIG. 5 is a flowchart illustrating a 3D printing method 500 according to an example embodiment. The method 500 may be implemented by a 3D printer configured in the same or similar manner as the 3D printer 100 shown in FIG. 1 (eg, by the control system 110 of the 3D printer 100). Of course, it should be understood that method 500 may be implemented by other types of 3D printers and/or by control systems of other types of 3D printers.

As represented by block 502, method 500 involves receiving data specifying a three-dimensional object. For example, block 502 may include the control system receiving a file describing the object for 3D printing, such as a Standard Tessellation Language (STL) file, an Object (OBJ) file, or a Polygon (PLY) file, among other possibilities. The control system may then determine a sequence of two-dimensional (eg, cross-sectional) shapes representing two or more layers of the three-dimensional object, as shown in block 504 . For example, at block 504, a software or firmware-based program may process the 3D model file to generate a layer sequence and output a file (eg, a G-code file) with instructions for a particular 3D printer.

As represented by block 504, the method 500 includes determining a shape of each of the two or more layers based at least in part on the received data. The shape of each layer can be represented by a series of voxels representing discrete locations on that layer that make up the 3D object. In some implementations, the layers are represented by a bitmap, where each bit corresponds to a particular light source and indicates whether to operate that particular light source, as represented by block 506 . A voxel may also include offset information that more accurately indicates the position of the voxel. In some cases, the shape of each layer is represented as vector graphics, or at a higher resolution than the 3D printer system is capable of printing. In these cases, method 500 involves rasterizing the received data to produce a discrete set of voxel values representing the 3D object at a resolution compatible with the particular 3D printer system. Then, at block 506, the control system operates the light source corresponding to the voxel value representing the shape of the layer of the 3D object.

As represented by block 508, the method 500 includes operating the determined light source to cure the layers of the three-dimensional object. The control system may operate the light source and the substrate (eg, by controlling mechanical features to which the substrate is attached) to sequentially form two or more layers of the three-dimensional object. After a given layer is formed, as represented by block 510, the control system may operate the substrate to lift the cured voxels from the rod. The control system can then operate the one or more light sources to cure voxels that form subsequent layers of the 3D object. A portion of the layer may be adhered to a portion of a previously formed layer. The operations of blocks 506 to 510 may be repeated to form the 3D object layer by layer.

FIG. 6 is a flowchart illustrating a 3D printing method 600 according to another example embodiment. Method 600 may be implemented by a 3D printer configured in the same or similar manner as 3D printer 100 shown in FIG. 1 (eg, by control system 110 of 3D printer 100). Of course, it should be understood that method 600 may be implemented by other types of 3D printers and/or by control systems of other types of 3D printers.

Blocks 602 and 604 include determining the shape of each layer of the 3D object. The operations of 602 and 604 may be the same as or similar to the operations of blocks 502 and 504 .

At block 606, the method 600 may include determining, for a particular layer, an operating light source to form voxels that make up the particular layer. The operations of block 606 may be similar to the operations of block 506 . However, in embodiments associated with method 600, the order in which the layers are formed may be reversed.

At block 608, the method 600 includes operating the light source to cure a particular layer of the 3D object. The operations of block 608 may be the same as or similar to those of block 508 .

At block 610, the method 600 includes lifting the substrate up until the lower ends of the rods are positioned on the top surface of the cured layer. The proximity of the lower end of the rod to the previously cured layer may be such that operating the light source causes the resin to cure against and adhere to the previously cured layer. The reference to the "top surface" of the cured layer in block 610 describes the topmost portion of the cured layer that is formed. It should be understood that layers may be formed from hollow voxels (ie, shells), and that "surface" refers to the apex of the hollow voxels. In an exemplary operation, if the same light source is operated for two consecutive layers, the vertically aligned voxels may adhere to each other to form a continuous hollow voxel.

In general, it should be understood that the voxel printing process described herein is applicable, in whole or in part, to other types of 3D printers. Furthermore, those skilled in the art will understand that aspects of the voxel printing process may be reversed or arranged in various ways. Other examples are possible.

VI. Conclusion

While various aspects of the present disclosure are disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. Therefore, the embodiments disclosed herein are for illustrative purposes and are not intended to be limiting, the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims (42)

1. A three-dimensional printing system, comprising:

a resin container defining a cavity therein;

a plurality of rods extending from an inner base surface of the resin container into the cavity;

a plurality of light sources arranged to emit radiation into the plurality of rods such that when the cavity contains liquid resin, radiation passing through a given one of the rods cures the liquid resin surrounding the given rod; and

a control system configured to:

(a) receiving data specifying a three-dimensional structure;

(b) determining a first shape and a second shape of a first layer and a second layer, respectively, from a plurality of layers that collectively form the three-dimensional structure;

(c) determining one or more of the light sources corresponding to the first shape;

(d) forming the first layer by operating one or more light sources, the one or more light sources corresponding to the first shape, to cure liquid resin in the first shape;

(e) determining one or more of the light sources corresponding to the second shape; and

(f) curing the liquid resin in the shape by operating one or more light sources to form the second layer on the surface of the first layer, the one or more light sources corresponding to the second shape.

2. The system of claim 1, wherein the control system is configured to determine one or more of the light sources corresponding to the first shape by:

determining coordinate values collectively representing the first shape, wherein each coordinate value corresponds to a particular light source; and

determining the one or more light sources as light sources corresponding to the determined coordinate values.

3. The system of claim 1, wherein the control system is configured to cure the layer of liquid resin in the first shape by operating one or more determined light sources corresponding to the first shape by:

energizing one or more determined light sources corresponding to the first shape for a predetermined length of time to form one or more voxels of cured resin comprising the first shape.

4. The system of claim 1, wherein the control system is further configured to individually control each of the plurality of light sources.

5. The system of claim 4, wherein the control system is further configured to individually control the intensity of each of the plurality of light sources.

6. The system of claim 1, wherein at least a portion of a given rod comprises a translucent material that scatters radiation emitted by a corresponding light-emitting element that passes through the given rod.

7. The system of claim 1, further comprising a robotic arm attached to a portion of a base plate, wherein the control system is further configured to control a position of the base plate by operating the robotic arm.

8. The system of claim 7, wherein the control system is configured to form each of the plurality of layers by:

(g) after the first layer of liquid resin having the first shape is cured, operating the robotic arm to move the base plate upward so that a bottom surface of the cured layer is positioned at a top end of the rod.

9. The system of claim 7, wherein the robotic arm is operable to move the base plate in at least three degrees of freedom.

10. The system of claim 9, wherein the control system is configured to form at least one of the plurality of layers by:

(h) operating the robotic arm to move the base plate laterally such that the cured first layer is offset from the plurality of rods.

11. The system of claim 9, wherein the control system is configured to operate the one or more determined light sources corresponding to the first shape to cure liquid resin in the first shape in a plurality of stages, wherein each stage comprises:

operating a subset of the one or more determined light sources to cure a portion of the first layer of liquid resin representing a portion of the first shape; and

operating the robotic arm to move the base plate laterally.

12. The system of claim 1, wherein the resin comprises a liquid resin that cures when exposed to Ultraviolet (UV) electromagnetic radiation.

13. The system of claim 12, wherein the plurality of light sources comprises a plurality of UV light sources.

14. The system of claim 1, wherein the plurality of rods are arranged as a two-dimensional lattice.

15. The system of claim 1, further comprising a non-stick coating covering at least a portion of the plurality of rods.

16. The system of claim 1, further comprising a vibration mechanism coupled to the plurality of rods configured to shake loose cured resin from the plurality of rods.

17. The system of claim 1, further comprising a cooling element coupled to the plurality of rods configured to thermally shrink the plurality of rods to separate the solidified resin from the plurality of rods.

18. The system of claim 1, further comprising a temperature-changing element coupled to the plurality of rods configured to change a temperature of the plurality of rods.

19. The system of claim 1, wherein the rod is operable to retract into the resin container through the inner base surface.

20. The system of claim 1, wherein each lever is operable to rotate in situ.

21. A three-dimensional printing system, comprising:

a resin container defining a cavity, wherein the cavity is defined in part by an inner base surface of the resin container;

a base plate suspended from above the resin container and configured to adhere to a cured resin;

a plurality of rods extending from a surface of the substrate into the cavity;

a plurality of light sources arranged to emit radiation into the plurality of rods such that when the cavity contains liquid resin, radiation passing through a given one of the rods cures the liquid resin surrounding the given rod; and

a control system configured to:

(a) receiving data specifying a three-dimensional structure;

(b) determining a first shape and a second shape of a first layer and a second layer, respectively, from a plurality of layers that collectively form the three-dimensional structure;

(c) determining one or more of the light sources corresponding to the first shape;

(d) forming the first layer by operating one or more determined light sources, the one or more determined light sources corresponding to the first shape, to cure liquid resin in the first shape;

(e) determining one or more of the light sources corresponding to the second shape; and

(f) curing a liquid resin in the second shape by operating one or more light sources to form the second layer on the surface of the first layer, the one or more light sources corresponding to the second shape.

22. The system of claim 21, wherein determining one or more of the light sources corresponding to the first shape comprises:

determining coordinate values collectively representing the first shape, wherein each coordinate value corresponds to a particular light source; and

determining the one or more light sources as light sources corresponding to the determined coordinate values.

23. A computer-implemented method, comprising:

receiving, by a three-dimensional (3D) printer, data specifying a layer of a three-dimensional (3D) structure to be printed;

selecting, by the 3D printer, a subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the subset of light sources corresponding to a layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a subset of the selected light sources corresponding to the layers of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset.

24. The method of claim 23, wherein the arrangement of hollow molds extends into the resin container from a bottom of the resin container, and wherein the light source is positioned below the resin container.

25. The method of claim 23, wherein the arrangement of hollow molds extends from a movable base plate associated with the 3D printer into the resin container, and wherein the light source is positioned within the base plate.

26. The method of claim 23, comprising:

receiving, by a three-dimensional printer, data specifying a second layer of a three-dimensional (3D) structure to be printed;

selecting, by a 3D printer, a second subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the second subset of light sources corresponding to a second layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a second subset of the selected light sources corresponding to a second layer of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset and adhere to the lifted, cured resin formed around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset and adhered to the lifted cured resin formed around the hollow mold associated with the light sources in the selected subset.

27. The method of claim 23, wherein the subset of light sources includes less than all of the light sources.

28. The method of claim 23, comprising dynamically adjusting the extent to which hollow molds in the arrangement extend into the resin container.

29. The method of claim 23, wherein the cured resin is lifted using an articulated robotic arm.

30. The method of claim 23, wherein the arrangement comprises a honeycomb pattern or a grid pattern of the hollow molds, the hollow molds being spaced apart from one another.

31. A non-transitory computer-readable storage medium encoded with a computer program, the program comprising instructions that, when executed by data processing apparatus, cause the data processing apparatus to perform operations comprising:

receiving, by a three-dimensional (3D) printer, data specifying a layer of a three-dimensional (3D) structure to be printed;

selecting, by the 3D printer, a subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the subset of light sources corresponding to a layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a subset of the selected light sources corresponding to the layers of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset.

32. The non-transitory computer readable storage medium of claim 31, wherein the arrangement of hollow molds extends into the resin container from a bottom of the resin container, and wherein the light source is positioned below the resin container.

33. The non-transitory computer readable storage medium of claim 31, wherein the arrangement of hollow molds extends from a movable base plate associated with the 3D printer into the resin container, and wherein the light source is positioned within the base plate.

34. The non-transitory computer-readable storage medium of claim 31, comprising:

receiving, by a three-dimensional printer, data specifying a second layer of a three-dimensional (3D) structure to be printed;

selecting, by a 3D printer, a second subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the second subset of light sources corresponding to a second layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a second subset of the selected light sources corresponding to a second layer of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset and adhere to the lifted, cured resin formed around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset and adhered to the lifted cured resin formed around the hollow mold associated with the light sources in the selected subset.

35. The non-transitory computer readable storage medium of claim 31, wherein the subset of light sources includes less than all of the light sources.

36. The non-transitory computer readable storage medium of claim 31, comprising dynamically adjusting an extent to which hollow molds in the arrangement extend into the resin container.

37. The non-transitory computer readable storage medium of claim 31, wherein the cured resin is lifted using an articulated robotic arm.

38. The non-transitory computer readable storage medium of claim 31, wherein the arrangement comprises a honeycomb pattern or a grid pattern of the hollow molds, the hollow molds being spaced apart from one another.

39. A three-dimensional printing system, comprising:

one or more computers and one or more storage devices storing instructions operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:

receiving, by a three-dimensional (3D) printer, data specifying a layer of a three-dimensional (3D) structure to be printed;

selecting, by the 3D printer, a subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the subset of light sources corresponding to a layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a subset of the selected light sources corresponding to the layers of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset.

40. The system of claim 39, wherein the arrangement of hollow molds extends into the resin container from a bottom of the resin container, and wherein the light source is positioned below the resin container.

41. The system of claim 39, wherein the arrangement of hollow molds extends from a movable base plate associated with the 3D printer into the resin container, and wherein the light source is positioned within the base plate.

42. The system of claim 39, comprising:

receiving, by a three-dimensional printer, data specifying a second layer of a three-dimensional (3D) structure to be printed;

selecting, by a 3D printer, a second subset of light sources from a plurality of light sources, the plurality of light sources each associated with a respective hollow mold in an arrangement of hollow molds that each extend into a resin container, the second subset of light sources corresponding to a second layer of the three-dimensional structure; and

activating, by the 3D printer, light sources in a second subset of the selected light sources corresponding to a second layer of the three-dimensional structure, thereby causing cured resin to form around the hollow mold associated with the light sources in the selected subset and adhere to the lifted, cured resin formed around the hollow mold associated with the light sources in the selected subset; and

lifting, by the 3D printer, the cured resin formed around the hollow mold associated with the light sources in the selected subset and adhered to the lifted cured resin formed around the hollow mold associated with the light sources in the selected subset.

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